Heretofore, the most advanced permanent splicing techniques have employed a V-grooved connector to achieve proper alignment of the fibers to be spliced, and then, either an aluminum pressure bond ring, epoxy, or a crimped sleeve is applied to join the fibers, end-to-end.
While these splicing techniques have been satisfactory for their intended purpose, they have been characterized by certain objectives. For instance, the small v-grooves in the connector are formed by special metal-embossing techniques which are not compatible with very low production. Furthermore, the v-groove connector is bulky and can only be used for cable splicing, if the fibers are arranged in a linear array. When employing bond rings, metal oxide bonds have a breaking strength of only two-thirds that of the fiber. When using epoxy bonding, proper alignment and connector block closure is dependent on the viscosity of the epoxy since the epoxy is in contact with the fiber along the V-groove As a result of the fiber being placed in the epoxy, care must be taken to prevent the epoxy from coming between the ends of the mating fibers, otherwise an epoxy having the proper optical properties must be used. When using crimped sleeves, stresses or microcracks can be induced at points of contact with the fiber.
As another alternative, permanent splices have been obtained by heating and fusing the fiber ends; however, this technique requires large power supplies, a complex and sensitive fiber alignment operation, and it is characterized by low fiber bond strengths.
To overcome the disadvantages experienced in prior techniques for splicing optical fibers, after considerable research and experimentation, the connector of the present invention has been devised which comprises, essentially, a glass sleeve having a precision cut bore formed therein. Funnel-shaped access openings are provided at each end of the bore for receiving the mating ends of the glass fibers to be spliced. In one embodiment, a permanent splice is made by applying a bonding agent and sealant to the funnel-shaped openings, and in another embodiment a retainer ring is employed to thereby provide a disconnectable splice.
By the construction and arrangement of the connector of the present invention, the precision bore in the glass sleeve provides self-alignment of the mating fiber ends, and the funnel-shaped openings facilitate rapid manual insertion of the fibers at each end of the sleeve.